Tobacco smoking remains the leading cause of preventable death in America and is viewed as “the No. 1 public health concern in the nation and the world” [1–3]. Tobacco’s impact on coronary heart disease and cancer is rivaled only by its role in Chronic Obstructive Pulmonary Disease (COPD), the third leading cause of death in America; smoking cessation and supplemental oxygen remain the only means to reduce mortality for this disease . In 2008, COPD directly accounted for 822,500 hospitalizations among American men and women and was listed as a contributory cause in an additional 3.8 million hospitalizations . In addition to the direct effects of smoking on these illnesses, there is a significant population of patients with asthma and other illnesses who are adversely affected by second-hand smoke [6–8].
Our understanding of the pathophysiology of COPD preceded large-scale tobacco policies, remaining largely informed by the 1960’s study of British industrial workers [9, 10]. This prospective study generated the first comprehensive insights into the clinical epidemiology of COPD and established FEV1 as the gold standard diagnostic test . Data showing that participants who quit smoking could normalize their rate of lung function decline, but not reverse existing pulmonary damage, was one of this study’s most important findings. This conclusion, however, had significant caveats as findings were based on a relatively small study sample and on self-reported smoking data. In 1976, these and other limitations led the authors to note that “Further studies are needed of the changes of FEV [forced expiratory volume] that occur in obstructed smokers when they stop smoking ….” [12, 13].
Despite this need for further research, there have been very few long-term cohort studies of smoking cessation and assessment of its effects on lung health and other disease parameters [14–16]. More recent observational studies have enrolled large numbers of participants and collected comprehensive clinical information [17, 18]. Despite the size and breadth of these investigations, early results of these studies highlight our present limitations in understanding lung disease, and question our understanding of its pathogenesis and diagnosis . For example, data published in 2011 from the ECLIPSE study found that in 2,163 COPD subjects, 15% had actual improvement in their lung function due to unknown contributory factors .
While the costs, constraints, and challenges of long-term observational studies and interventional trials are a serious impediment to understanding the progression of chronic diseases, a natural experiment is currently underway in U.S. prisons. As of 2008, more than half of U.S. states as well as the Federal Bureau of Prisons (BOP) had a total tobacco ban; the BOP ban began in 2004 . Several studies have begun to delineate the impact of these bans. The existing literature, however, has generally focused on characterizing smokers’ addiction and behavior in partial ban settings or over limited periods of time. [22–25]. Our proposed longitudinal study will be able to address a number of important unanswered questions in the field through the use of a study population with and without medical co-morbidities, under a verifiable complete smoking ban over an extended period of follow-up. The present investigation will, for the first time, allow a comprehensive and systematic assessment of the effects of enforced smoking abstinence on respiratory symptoms, pulmonary physiology, biomarkers, and outcomes known to relate to an individual’s long-term survival and health-related quality of life. Though conducted in a prison setting, the subjective, clinical, pulmonary function, and biomarker results would apply to the general population.
We hypothesize our natural history study will find distinct subgroup patterns of improvement, plateau, or decline in terms of health service utilization, lung impairment, and biomarkers. We see this variability as a contrast to the traditional course as interpreted from Fletcher and Peto’s data and more consistent with the ECLIPSE study cited above and recent findings in biomarker patterns [26–29]. If found, such subgroups may allow for the development of targeted therapeutic care.
In addition to information on pulmonary health, the study also allows for considerable impact on public health. With 1% of the U.S. population being incarcerated in a given year, and more than 12% of U.S. smokers released annually from incarceration, exploring a durable means of tobacco abstinence post-release could have a powerful health effect beyond prison . Several studies have shown substantial cardiovascular mortality associated with release from prison; this risk may be due to the high prevalence of tobacco use in the corrections population . Our protocol will allow for a deeper understanding of nicotine addiction in the setting of long-term enforced abstinence and provide for future informed interventions prior to release. Understanding tobacco addiction during and after prison may also help support smoking cessation and prevention efforts in other restricted settings.